Safety should always be the main consideration for any DIYer who works with electricity, so testing tools are a must. An outlet tester, also called a receptacle tester, plugs into an electrical outlet to let you know if it's "hot" -- i.e., conducting electricity. You can find out if the outlet has been wired properly, and it can also be used to diagnose basic problems. A continuity tester does the same thing for a fuse, a light switch or the wiring in a light fixture. A voltage tester indicates if a cable has power running through it, and the non-contact variety are the safest tools for the novice. A volt meter, or volt-ohmeter (VOM), gives an actual voltage reading so you can make sure it's running at the correct rate.